Transformer cooler



May 5, 1931. D. T. MaCLEOD TRANSFORMER COOLER Filed March 3 1928 7 Z M677, 707. W5/Wl f//C ZZ@ 07,25

Patented May 5, 1931 LSG-3,5%

UNITED STATES PATENT OFFICE DANIEL T. DIACLEOD, OF BIILVAUKEE, WISCONSIN, ASSIGNOR TO PERFEX CORPORA- TION, OF MILVIAUKEE, VVSCONSN, A CORPORATION OF WISCONSIN TRANSFORM'ER COOLER Application filed March 3,

' This invention relates to means for cooling electrical transformers and particularly the type in which an oil bath is employed for insulating and cooling the transformer coils. :fi lt is customary to surround transformer coils by an oil bath to provide external radiator tubes communicating with the transformer rousing near the top and botto-m whereby the oil contents may circulate on a thermo-Siphon principle so as to cool the oil bath by the dissipation of heat to the externa-l atmosphere. Such arrangements are, how ever, comparatively ineric nt because the eil becomes sluggish in cold weather and does not circulate rrely and in het weather the loss of heat is insullicient to prevent an excessive rise of temperature in the bath when the transformer is under load. Such radiators are sometimes arranged to take advantage of the Wind by grouping radiator' coils or tubes on various sides of the transformer but even under the best of conditions no more than two groups of such radiators will work effectively at one time and since the radiators and housing are subjected to the heat of the sun and the external atmosphere, they have but little cooling effect during eX- tremely hot summer weather.

The main object of this invention is to provide improved means for coolingl the oil bath of electrical transformers to maintain the same within predetermined ranges of temperature regardless of load and atmospheric conditions; and to provide an improved apparatus of this type wherein the cooling medium will be circulated mechanically through and exteriorly of the transformer under thermostatic control for automatically adjusting the cooling effect to the load. n

These objects are accomplished by the construction shown in the accompanying drawings in which:

Figure l is a side elevation of an electrical transformer provided with cooling devices in accordance with the present invention.

Fig. 2 is an elevation of the radiator viewed from the line 2 2 of Fig. l, the core of the radiator being broken away and indicated only by a fragmentary portion thereof in 1928. Serial No. 258,854.

order to show the arrangement of the fan and motor at the rear thereof.

In the form shown in Vthe drawings the transformer is provided with an oil tight housing` l adapted to contain an oil bath in which the transformer coils (not shown) are submerged. This housing is provided with a jacket 2 packed with suitable insulating material 3 for protecting the .housing from being heated by the sun or the surrounding atmosphere in hot weather. Heat transfer apparatus preferably in the form of a radiator 4 of automotive type is mounted exteriorly of and preferably at one side of the housing l and its upper tank or header 5 is connected with the upper portion of the transformer housingl l by a pipe (3. The lower tank 7 of the radiator is connected by a pipe 8 with a circulating pump 9 which in turn is connected by a pipe l0 with the lower part of the housing l. These connections are preferably provided with headers ll and l2 respectively each having a series of ports in communication with the interior of the housing for better circulation of the oil bath.

The core 13 of the radiator may be of any usual type; for example, one having vertical passages between the top and lower tanks for circulation of the oil and having transverse air passages.

An electric motor 1d is mounted on the supportingframe and suitably connected with the circulating pump 9 and an exhaust fan for sin'iultaneous oi'leration of said pump and fan The fan also smrounded by a fan housing lo as in certain types of automotive radiators for improving the efficiency of the an' low through the radiator.

The motor is controlled by a switch 1T which in turn is controlled by a the'rn'iostat 18 having thermal couples or other heat sensitive means extending into the interior of the housing l so as to be sensitive to changes in temperature of the oil bath within the housing.

The operation of the device shown is as follows:

The thermostat 1S which may be of any suitable type is constructed or adjusted so as to close the switch 1T connecting the motor 14 with its source of power, indicated by the line wires 19, when the temperature of the oil bath is in the vicinity of 14() degrees or such other temperature as may be predetermined and to open the switch when the oil temperature falls, say, for example, 5 degrees below such predetermined temperature. Thus the cooling device will operate intermittently as required, depending upon the electric load on the transformer which tends to heat t-he oil and the cooling effect of the radiator. It will be understood that the motor under its automatic thermostatic control Yill operate only to the extent' necessary to rei duce the temperature of the oil bath to the degree for which the thermostat is set and that, of course, the periods ofl operation will be longer in the summer when the atmosphere is hot than in the' winter, but it apparent that a singlek radiator can'v take care of the entire cooling requirements of a large transformer or of aV series or group of transformers which are simultaneously operated.

By reason of the improved cooling effect of the herein described apparatus and the insulation of the housing of the transformer, the oil bath will be protected from excessive heating in summer and excessive cooling in winter and the ideal isothermic condition will be approximated. There will accordingly be less evaporation of the oil, the sizes of the transformer and its housing` may be reduced, a cheaper quality of oil may be used, and it will be unnecessary to change the oil with change of season. I f

Although but one specific embodiment of this invent-ion has been herein shown and described, it will be understood that details of the' construction shown may bek altered or omitted without departing fromy the spirit of this invention as defined by the -following' claims.

l claim 1. A cooling system for transformers cemprising a casing surrounding the transformer and containing a dielectric cooling liquid, a heat insulating jacket for said casing operating to prevent direct and uncontrolled heat exchange between the liquid in said easing and the environment of the casing, a liquid circulating` system connected to said casing and communicating with the interior thereof, a radiator embodied in said liquid circulating system and disposed exteriorly of said casing, a pump incorporated in said liquid circulating lsystem to positively circulate the liquid through said system, a'. fan for impelling a current of air through'said radiator, motor means for driving said fain and said pump, and means responsive to the temperature of the liquid within the casing for regulating the operation of said motor means whereby to maintain a predetermined temperature condition in said casing.

2. A cooling system for transformers comprising a casing surrounding the transformer and containing a dielectric cooling liquid, a heat insulating jacket for said casing operating to preventdirect and uncontrolled heat exchange between the liquid in said casing and the environment of the casing, a liquid irculating system connected to said casing and including pipe lines communicating with the upper and lower portions thereof, a radiator disposed exteriorly of the casing and comprising upper and lower tanks connected to said pipe lines and a core interposed between and connecting the tanks and having liquid' passages and air passages, a pump incorporated in said liquid circulating system to positively circulate the liquid through said casing, said pipe lines, and through said radiator, a fan for impelling a current of air through the air passages of said core, motor means for driving said fan and said pump, .zA

and means responsive to the temperature of the liquid for regulating the operation of said motor means whereby to maintain a predetermined temperature condition in said casing.

Signed at Chicago, Illinois, this 29th day of fifebruary` 1928.

DANIEL T. MACLEOD.

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